Add proxy app to manager upon starting

We also check if proxy is "running" and if it is not, we remove proc
object to restart the proxy. This way proxy will be restarted only when user
does it via lancher.

Author: mahendrapaipuri

jupyter_server_proxy/handlers.py

@@ -23,6 +23,7 @@
 from .unixsock import UnixResolver
 from .utils import call_with_asked_args
 from .websocket import WebSocketHandlerMixin, pingable_ws_connect
+from .manager import manager
 
 
 class RewritableResponse(HasTraits):
@@ -800,9 +801,17 @@ async def ensure_process(self):
         # Invariant here should be: when lock isn't being held, either 'proc' is in state &
         # running, or not.
         async with self.state["proc_lock"]:
+
+            # If the server process is terminated via Runningsessions or killed
+            # outside of jsp, we should be able to restart the process. If
+            # process is not in running stated, remove proc object and restart
+            # the process
+            if 'proc' in self.state:
+                if not self.state['proc'].running:
+                    del self.state['proc']
+
             if "proc" not in self.state:
                 # FIXME: Prevent races here
-                # FIXME: Handle graceful exits of spawned processes here
 
                 # When command option isn't truthy, it means its a process not
                 # to be managed/started by jupyter-server-proxy. This means we
@@ -836,6 +845,10 @@ async def ensure_process(self):
                     if not is_ready:
                         await proc.kill()
                         raise web.HTTPError(500, f"could not start {self.name} in time")
+
+                    # If process started succesfully, add it to manager
+                    # Add the server proxy app to manager
+                    await manager.add_server_proxy_app(self.name, self.base_url, cmd, self.port, proc)
                 except:
                     # Make sure we remove proc from state in any error condition
                     del self.state["proc"]